The invention relates to a shaving razor and a blade unit therefor with an improved guard.
Shaving razors often consist of a handle and a replaceable cartridge in which one or more blades are mounted in a plastic housing. U.S. Pat. No. 5,918,369 describes a shaving razor including a replaceable cartridge that has a blade unit that is pivotally connected to an interconnect member that is in turn connected to a handle. The blade unit includes a guard having resilient fins in front of the blades to engage the skin surface and a lubricating strip behind the blades.
In one aspect, the invention features, in general, a shaving razor blade unit that has a plurality of blades and a guard that includes two groups of rows of elongated, elastomeric fins arranged generally parallel to the cutting edges of the blades. The first group of fins has tips with generally uniform base to tip heights of a first dimension, and the second group in has tips with generally uniform base to tip heights of a second dimension, the second dimension being less than one fifth of the first dimension.
In another aspect, the invention features, in general, a shaving razor blade unit that has a plurality of blades and a guard that includes a plurality of rows of elongated, elastomeric fins arranged generally parallel to the cutting edge and having base to tip heights less than 0.15 mm.
In another aspect, the invention features, in general, a shaving razor blade unit that has a plurality of blades and a guard that includes a plurality of rows of elongated, elastomeric fins arranged generally parallel to the cutting edge, the fins being the last skin engaging structure contacted by a user""s skin before contacting the blades.
Particular embodiments of the invention may include one or more of the following features. The fins in the two-group embodiments and in the embodiments where the fins are the last structure in front of the blades, the fins are small fins which also have a base to tip height of less than 0.15 mm. Preferably these small fins have a base to tip height of between 0.06 and 0.08 mm. Preferably there are at least three fins in each group.
In the two-group embodiment, some of the fins in the first group have tips above a plane passing through the cutting edges; some of the fins in a first group have some of the tips below the plane, and the second group of fins have tips above a plane. The tips in the first group of fins have a height between 0.4 mm and 0.8 mm, most preferably between 0.6 mm and 0.7 mm. They fins in a first group have an included angle less than 14 degrees most preferably about 12 degrees. The distance from the first fin of the first group to the last fin of the first group is between 2.0 mm and 3.5 mm. They first group of fins includes a leading group of fins and a trailing group of fins, the leading group having tips having increasing elevation with respect to a plane passing through the cutting edges, the trailing group having tips of generally uniform position relative to the plane.
Preferably the blades are movably mounted with respect to the housing. Preferably the blade unit is connected to a pivotal structure to permit the blades in to pivot with respect to a handle.
In another aspect, the invention features a shaving razor including a handle and a blade unit as already described connected to handle.
Embodiments of the invention may include one or more of the following advantages. The fins tend to stimulate and stretch the skin in front of the blades, tending to improve comfort and proper positioning of the skin for cutting of hairs. The fins that provide a resilient structure as the last skin contacting member before engagement by the first blade act to improve skin stretching and improve comfort. In addition, the user can adjust the geometry of the exposure of the first blade and the blade tangent angle by pressing harder on the elastomeric fins that are the last skin contacting structure before the blade. In the two group embodiments, increasing the elevation of fins tends to gradually increase skin contact and causes the tips to conform to the skin flow during shaving. The narrow included angle profile of the larger fins improves fin flexibility, which helps to stretch the skin, thereby setting up the hairs for improved cutting. The use of a large number of fins improves skin engagement.
Other advantages and features of the invention will be apparent from the following description of a preferred embodiment thereof.